Ada noob here! Is Ada widely used?
in [ADA]
|
Prev: Symbolic tracebacks on Debian (Was: About static libraries and Debian policy)
Next: Gnat cross compiler
From: Georg Bauhaus on 7 Jun 2010 10:12 On 07.06.10 14:22, Dmitry A. Kazakov wrote: > On Mon, 07 Jun 2010 13:13:18 +0200, Georg Bauhaus wrote: > >> DbC, however, has to do with designing components of the ship. >> You can have rescue clauses (exception handlers) >> in DbC. > > To whom should Titanic have sent the exception? To the humpback whales? As I said, this is not an exception raised in some component part, the ship is damaged and is going to sind. The frame of reference for "exceptional" is a different one. >> Exceptional situations is "unprogrammed" exceptional state, >> since this is what "exceptional" is about, if anything. > > Any state is programmed. In an trivial sense, yes, every exceptional state is a state.... "Boring!", as some say. > This includes the exceptional ones. When bug > happens, the program is in no state. Erh, are you sure?
From: Yannick Duchêne (Hibou57) on 7 Jun 2010 10:31 Le Mon, 07 Jun 2010 16:12:38 +0200, Georg Bauhaus <rm.dash-bauhaus(a)futureapps.de> a écrit: >> This includes the exceptional ones. When bug >> happens, the program is in no state. > > Erh, are you sure? May be when the CPU enters a double-fault state ? (half-joking) -- There is even better than a pragma Assert: a SPARK --# check. --# check C and WhoKnowWhat and YouKnowWho; --# assert Ada; -- i.e. forget about previous premises which leads to conclusion -- and start with new conclusion as premise.
From: Yannick Duchêne (Hibou57) on 7 Jun 2010 10:44 Le Mon, 07 Jun 2010 15:27:45 +0200, Dmitry A. Kazakov <mailbox(a)dmitry-kazakov.de> a écrit: > They will rather distract from design in favor > debugging. As an old Eiffel âadvocatorâ, I can say no, as long as you read contract clauses before using any component holding such a contract (just like you have to know the signature of a subprogram before being able to use it). And whenever an error occurred, which is caught (likely early) by a clause violation, you then have an interpretation of the error. There is nothing like an interpretation, when in a debugger, you see this variable X has this value Y which turns into the Z behavior. Even if a clause violation pass control to a debugger (I had created my own in that purpose with SmallEiffel), you still have a debugger with an interpretation of an erroneous state. > Ada was designed as a language of little or no debugging. > Unfortunately it rapidly loses the ground. Agree. But there is no magic keyword, no magic syntactic construct, this target needs paradigm, process and construction techniques. And this is the purpose of DbC. Ada needs something to target âlittle or no debuggingâ, it cannot do it by-itself. I agree there are other ways, more strict and formal ways to achieve the same, ... however, this would unlikely meet a large community agreement (for the reasons given before).. -- There is even better than a pragma Assert: a SPARK --# check. --# check C and WhoKnowWhat and YouKnowWho; --# assert Ada; -- i.e. forget about previous premises which leads to conclusion -- and start with new conclusion as premise.
From: Yannick Duchêne (Hibou57) on 7 Jun 2010 10:48 Le Mon, 07 Jun 2010 16:09:37 +0200, Georg Bauhaus <rm.dash-bauhaus(a)futureapps.de> a écrit: > I still wonder why one would not want to > specify more than the subtype constraints can achieve Indeed, I oftenly had this in mind (what a type system will never be able to do). -- There is even better than a pragma Assert: a SPARK --# check. --# check C and WhoKnowWhat and YouKnowWho; --# assert Ada; -- i.e. forget about previous premises which leads to conclusion -- and start with new conclusion as premise.
From: Dmitry A. Kazakov on 7 Jun 2010 10:51
On Mon, 07 Jun 2010 16:12:38 +0200, Georg Bauhaus wrote: > On 07.06.10 14:22, Dmitry A. Kazakov wrote: >> This includes the exceptional ones. When bug >> happens, the program is in no state. > > Erh, are you sure? Yes I am. Any program state is defined, it has some sematic interpretation in the domain. Bug is when you have lost this synchronization. Meaningless state is no state. -- Regards, Dmitry A. Kazakov http://www.dmitry-kazakov.de |